1. Field of the Invention
The present invention relates to a magnetic disk apparatus and, more particularly, to a magnetic disk apparatus suitable for achieving a small size, a large capacity and high-speed access, and a magnetic head supporting device for use in such a magnetic disk apparatus.
2. Description of the Related Art
In recent years, it has been strongly demanded that a magnetic disk apparatus have a reduced size, an increased capacity and increased access speed while ensuring high reliability. In order to meet these demands, various proposals have been made. In particular, in order to reduce the size of a magnetic disk apparatus, the diameter of a magnetic disk has been decreased, and the spacing between stacked magnetic disks has been decreased. Among the most recent apparatuses for magnetic disks of 3.5 inches, those having a spacing of 3 mm between disks are being sold on the market. As the size of magnetic disk apparatuses has thus been reduced, the size of magnetic head supporting devices for such apparatuses has been rapidly reduced. An example of such size reduction is shown in Japanese Patent Unexamined Publication No. 2-226512. This publication discloses a method in which a slider having a magnetic head mounted thereon is directly formed on the surface of a suspension by a film forming process.
In the disclosed art, the slider and the suspension, are formed of different materials. It has been conventional that a suspension, which must have a spring structure for supporting a slider, is generally formed of a metal material while the slider, which is to contact a magnetic disk, is normally formed of an abrasion-resistant material.
As a result, in a construction wherein a slider is formed on a suspension by a film forming process, as in the above-described prior art, no consideration has been given to the bonding strength between the slider and the suspension (that is, the bonding strength between the different materials), thus involving the possibility that the slider may be separated by contacting the magnetic disk. Further, the slider may tend to be deformed due to factors such as a difference in coefficients of thermal expansion of the different materials for the slider and the suspension, thereby involving the risk of the slider flying characteristic being adversely influenced. In addition, since it is difficult in a currently practiced film forming process to achieve a surface roughness of not more than 10 nm while assuring that the flying surface of the slider is distant from the suspension by a certain slider thickness (height) required to mount the magnetic head, the slider cannot function sufficiently. Thus, it has been impossible to assure that the magnetic disk apparatus can provide high reliability.